Diesel power hammer



Sept. 21, 1937. H. CORDES 2,093,634

DIESEL POWER HAMMER 1,0 6 q 48 -1 8 o o a v Q:

-p i 4 fi er-9w- @104 J Sept. 21, 1937. H. CORDES DIESEL POWER HAMMER Filed May 9, 1936 1 2 Sheets-Sheet 2 50 the striking position,

Pstenies'sepi. 21, 1937 Es PATENT or creases mnsnr. rowan HAMMER.

Hugo Cordes. Altona, Germany Application May 9, 1936, Serial No. 753,156 In Germany July 7, 1935 4 Claims. (01. 123-4) Among the so-called Diesel power hammers one form ofapparatus (U. 8. Patent 929,696) is known.

in which a cylinder rests on the impactplate,

while a pistonis acting as a ram, and in which,

further, the cylinder bottom contains 'a bore inwhich a particular hammer block moves. This known formof apparatus contains a differential ram the upper part of which may act as an impact body, the combustionspace being arranged at the v 1 end of its lower part with its comparatively small diameter. "However, this known form of apparatus does not allow of injecting the fuel from outwards into pure air, as the impact face is of annular form and obturatea the injecting cham bar formed by recesses in the striking parts.

The present invention equally concerns a device of this kind, which, however, differs fundamentah' ly from the known form in that the useful impact surface is arranged in the central part of the hammer block and of the ram, and that the injecting chamber is arranged outside of the impact surface. Y

The injecting chamber could for example be obtained in such a .way that the piston and the hammer block each are-designed with a projection of comparatively small diameter. Of course, the hammer block only may be equipped with a projection of this sort, as it is only'fundamentally important that between the impact body a moving as a ram within the cylinder and the hammer block repcsing on the impact plate an in- Jection chamber be left free while the ram strikes the'hamme'rblock. The injection chamber may, for example, be provided in the form of'pockets containedin the cylinder wall, or itmay be arranged symmetrlcally or asymmetrically relative to the hammer block, without amodification of the principle of the invention. 7

Further, it is preferable to have the piston go entirely clear of the combustion chamber, by which means a better scavenging effect with. fresh air and better cooling are obtained.

In the accompanying drawings two forms ofthe new apparatus are shown, viz:

Fig. 1 shows one form of apparatus in a substantially central longitudinal section, the piston being raised, c g Fig. 2 shows a centrallongitudinal section at right angles to that of Fig. 1 with the piston in Fig. 3 is another form of apparatus with a combustion chamber arranged laterally, the lower part of the entire device being shown only, Fig. 3

being a central longitudinal section,

. 55 Fig. 4 shows the same design in a central longitudinal section, at right angles to that of Fig. 3,

Fig. 5 is a section along line 5-5 in Figure 4. The hammer body comprises an upper part In, a middle part lb and a lower part lc. The-lower part contains a hammer block 2; it isobturated 5 against the part. lc by means of piston rings 3. The hammer block 2 rests, by means of a spherical surface, upon the impact-plate l which is connected with the hammer body by means of pins 5, thus permitting a certain longitudinal displacel0 ment as well as a'certain inclination relative to the centre line -of the hammer body at a 'certain angle in every direction. The hammer block 2 is, further, equipped with a shoulder against which the hammer body rests. It can freely move 15 in the longitudinal direction of the hammer body. and its upper face bears a central abutment. The

lower part 10 of the hammer body contains a cavity forming a combustion chamber 8 and carries a fuel pump 1 with an injecting nozzle 8 20 which is actuated by means of a curved lever 9 and a push rod iii. The push rod III is moved downwards by the impact body 12, and it is actuated in an upward direction by spring I I when the shoullower part l2b. Both parts of the impact. body 30 are provided with piston rings l3 and H. The, central part of the lower section of the impactbody I2 is provided with an abutment I! which may deliver an impact blow to the abutment lb of the hammer block 2.

The central part lb of the hammer body is equipped with an air filter and inlet valve ll through which air may enter but which will prevent air from escaping. This valve I1 is ar-' ranged at substantially the same height as an 40 overflow valve [8' permitting air to leave the cylindrical space of the overflow duct I9, but the action of which cannot be reversed. The duct I9 ends within the combustion chamber 6 in the form of an open tuyere 29 or, as shown in Figures .45 3 to 5, in a check valve 2| located near the lower end of the combustion chamber and which allows the air to escape from the duct l9, but prevents it from entering therein. According to'the design in Figures 3 to 5, the overflowvalve l8 may be omitted.

In the head Ia of the hammer body, a sliding rod 22 is arranged so as to-be movable longitudinally; it can be arrested in its-upper position by means of a locking pawl 23. At the same time carries hooks 24 which fit into a corresponding recess at the upper part of impact body I2.

The apparatus operates as follows: -To start the hammer, the winch rope of th pile driver is connected to the sliding rod 22. When the winch "rope is released, rod 22 carrying the hooks 24 will drop, and the hooks 24 will engage the impactbody I2 which thus canbe lifted by means of the winch. Upon the impact body I2 having reached its upper position, the hooks 24 are released. As soon as the hooks 24 have been released, the impact body I2 will drop freely, thus producing within the combustion chamber 6 a compression of the air contained therein; at the same time air is drawn into the space provided above the impact bodythrough inlet valve I1. After the air has been compressed, the impact body will strike the hammer block 2. In this way, the air will be driven from the central part to the circumference and will be caught in the space 25. This space, of annular form, surrounds the abutment IS in the embodiment shown in Figures 1 and 2. In the modification shown in Figures 8 to 5, the annular space is of very restricted dimensions, and space 25 has been provided as a cavity in the wall of the combustion chamber.. These two conceptions differ in that space 25- always maintains a constant volume as shown in Figures 3 to 5, without being influenced by the relative positions of the hammer block 2 and the hammer body. However, with a design as shown inFigures 1 and 2 the space 25 is reduced in volume in accordance with the difference in diameter. In this way the compression of the air will reach a higher degree, and by the action of the surplus surface, the hammer body is given an additional tendency to descend. In this way, the hammer body will follow the hammer block at a faster rate than it would without the effect of the compressed air. This feature is important whenever the soil yields quickly so that hammer block 2 descends at a very fast rate and that in the embodiment of Figures 3 to 5 the connection between space 25 A pletely transposed into the cyl der wall.

and the contact face between parts I2 and 2 could be impaired. It is true that in this way a portion of the impact energy would be lost and transformed into compression work.. The fuel jet will enter space 25 through the nozzle contained in its lower part, as shown-in Figure 2; thus the impact body I2 when descending cannot interfere with the fuel jet. Further, in order to obtain for the atomization of the fuel a space of. greater height the cylinder bottom can be remust be so large as to leave only little space for the space above mentioned. The space within the cylinder bore can, then, be completed by means of a cast-in or machined cavity of the cylinder body. The design shown in Figures 3 to 5 shows the last stage in this direction in which the aforementioned space hasbeen nearly com/- The injection of the fuel into the compressed air is effected by means of a shoulder of the difl'erential impact body I2 which pushes. the pin l0 downwards against the tension of spring II. Pin It may bear a roller which slides along the the rod is tightened in its seat in the head Ia so as to prevent air from escaping. Rod,22

the impact body I2. After the fuel pump has reached its full stroke, the roller may proceed a bit further, thus allowing the impact body to enter the cylinder for some further distance. By this time the injection of fuel has practically ceased, and the ignition is caused by a correspondingly intense compression of the air. As a consequence of the combustion, the impact body is thrown upwards, and after the exhaust slots 26 have been opened, the hot gases will escape. A short time afterwards the canal I8 shown in Figures 1 and 2 opens and the air in the space above which has also been compressed by the rising impact body,- can enter the combustion space through valve I8 and nozzle 20. As the cold gases are heavier than the combustion products,

' they will penetrate into the combustion chamber which process is favored by the circumstance that nozzle 20 is directed downwards. The impact body will entirely get out of the combustion cylinder, by which way the scavenging process of the combustion chamber is completed. Below the portion I 2a of the impact body the exhaust gases and the surplus cold air escape through opening 21 in the cylinder casing. As soon as the impact body has reached a suflicient height to obturate overflow valve I8, the air contained in the space above impact body I2 will be compressed. This compressed air causes a back pressure acting on the impact body and delays its ascent, while at the same time it tends to lift the hammer body. Thus, an acceleration of the rate of working is obtained, because the impact body will rise for an amount which is smaller than that which would correspond to its natural rising height. As the weight of the hammer body must be considerable to obtain an appreciable acceleration of impact body I2, the air cushion which, of course, could also be replaced with some other elastic means, as for example a spring or a rubber bumpencould be omitted in those cases where a rapid succession of blows is not desired. It must still be pointed out that thetechnical details of the catching device for the impact body may be designed in any suitable way and that this catching device might even be omitted, for example, if starting were effected by compressed air.

I claim:

-1. In a Diesel power hammer, in combination a housing containing a combustion chamber, a hammer block formed with an abutment extending through the bottom of said housing, an impact body movably mounted-in said housing and formed with a reduced piston to fit said combustion chamber and adapted to strike said hammer block, said impact body and hammer block having centrally disposed impact faces, said housing having a fuel receiving space laterally of the impact face of said hammer block, a means for injecting fuel into said space, means for admitting air to said combustion chamber, and means for raising said impact body in said housing for starting pu poses. I

2. In a Diesel power hammer, in combination a housing containing a combustion chamber, a hammer block formed withan abutment extending through the bottom of said housing, an impact bodymovably mounted in said housing and formed with a reduced piston to fit said combusher and pted to strike ma hammer means for'iniecting'fuel into said space, means for raising said impact body in said housing for starting purposes, means for securely guiding 5 said impact body in the upperpart of said housing, the latter being so dimensioned as to permit the piston part of said impact body to completely leave said combustion chamber after each impact thereby" admitting scavenging air to said 10 combustion chamber. I

3. In a Diesel power hammer, in combination a housing containing a combustion chamber, a .hammer block formed with a shoulder for supporting said housing and with an abutment ex- 15 tending through the bottom of said housing, an

impact body movably mounted insaid housing and formed with a reduced piston to fit saidcombustion chamber and adapted to strike said hammer block, said housing having a fuel receiving 20 space laterally of the impact face of said hammer block, means for injecting fuel into said space, means for admittingair to said combustion chamber, means for raising said impact body A 3093,1334 block, said housing having a fuel receiving space,

in said housing for starting P ses, an impact plate formed with a spherical seat for said hammer block, and means connecting said impact plate to said housing sons to permit slight angular and longitudinal adjustment of said impact plate on said housing.

4. -In a Diesel power hammer, in combination Zmer block, means for injecting fuel into said space, means for admitting air to said combustion chamber, means for raising said impact body in said housing for starting purposes, means in the upp r Pa t of said housing for cushioning the upward stroke of said impact body, r a HUGO CORDES. 

